It's no secret that Major League Baseball players can hit, catch and throw far better than the rest of us, but these abilities don't just come from their above-average physical prowess. As Yogi Berra once infamously said, "Baseball is 90 percent mental; the other half is physical."
In a book that came out earlier this year, "The Psychology of Baseball," psychologist Mike Stadler of the University of Missouri took a look inside that "90 percent" to see what mental abilities and traits major leaguers have that allow them to succeed in the high-pressure, precise and highly psychological game of baseball.
"Baseball is impossible without psychology: impossible to play, and impossible to appreciate fully as a fan," Stadler wrote. "Watch any game, and most of what you see is thinking."
While all sports involve a certain amount of psychology to strategize and plan in given situations, it is particularly apparent in baseball.
"Baseball is different … because it does give players a lot more time to think before each action," Stadler said.
Having all that time to think means that baseball players need sharp cognitive skills to complement their physical abilities to succeed in the major leagues.
"You have to be one in 2 million to have the total package of physical and psychological abilities required to succeed in baseball at its highest levels of competition," Stadler wrote.
Most baseball players have extraordinary capabilities to coordinate physical and mental processes, including fast reaction times, focus and high visual acuity.
Studies conducted by Columbia University on Babe Ruth while he was playing showed that he could react to visual and sound cues much faster than the average person and that he had better hand-eye coordination than 98.8 percent of the population.
Baseball players tend to have excellent vision, which allows them to see things like the spin on a curveball hurtling toward them at home plate, cues they can use to get a hit.
"Most baseball players do have pretty good vision; a huge proportion of them test at better than 20/20," Stadler said.
Reaction time is also critical in baseball, and the better players seem to have better reaction times. There's some suggestion that this could simply be a matter of having more practice, "but you actually find even within really highly skilled players, the players at the higher end, the faster reaction times still tend to have higher batting averages and be slightly better hitters," Stadler told LiveScience.
Hitters also employ prediction, a psychological process, to help them hit the ball. They use what they know about a pitcher from previous times they have hit against him and what they know about the game situation (how many outs there are, what the count is, whether there are any players on the bases) to guess what ball the pitcher might throw next. This prediction is critical because they have so little time to react to a pitch (the ball only takes four-tenths of a second to cross the plate after it is released).
"The physical nature of the game, and especially the speed of some of the things that have to happen means that you just have to have a lot of mental preparation or it would be impossible," Stadler said.
Baseball players also tend to have excellent focus, which allows them to drown out external factors such as the crowd noise and any worries over a recent losing streak. Roger Clemens, who pitched for the New York Yankees this season, once commented that when he was focused, all he saw was the catcher, but when he lost his focus, he was "seeing the crowd, not just the catcher."
Besides the physical process and acute mental abilities, successful baseball players also typically have certain personality traits—this is perhaps best exemplified by the diverging career paths of Darryl Strawberry and Billy Beane, Stadler said.
Both players were drafted by the Mets in 1980 (Strawberry was picked much higher than Beane)—the team even had trouble deciding which player to pick first because of their comparable athletic abilities. But while Strawberry came to be one of the best hitters in baseball, Beane couldn't hack it in the majors (though he went on to become General Manager of the Oakland A's).
"Beane was just sort of crushed by the pressure of the batter's box, just didn't have that sort of self-confidence, almost arrogance, just to know, 'I do this well. I'm fine. So what I just struck out, I'm going to hit next time,'" Stadler said.
Strawberry displayed the exact opposite reaction: "You can look at some of Strawberry's early interviews when he broke into the league and was struggling a little bit as player's naturally do, but he, even then he just said, 'I know I'm a good hitter. I'm going to hit plenty of home runs,'" Stadler said. "He just wasn't worried about the pressure."
What makes up what Stadler calls a "baseball personality" like Strawberry's was described by personality test called the Athletic Motivation Inventory (AMI) developed by William Winslow, still used by many baseball teams today to sort out which players have the personality traits it takes to succeed in major-league baseball.
The traits that seemed to be most important in baseball were some of the ones Strawberry clearly displayed: self-confidence, mental toughness (or how well a player rebounds from failure), emotional control in stressful situations and a slight tendency toward aggression (in this context, the desire to make things happen).
Strawberry's self-confidence and mental toughness are particularly apparent in his comments and are critical traits in a major-league hitter.
"If you're a hitter, you fail two-thirds of the time, so you can imagine why self-confidence would be really important," Stadler said. "You have to keep, sort of keep plowing through, even though you just struck out four times in a game or something"
These traits are the same that are important in individual sports such as tennis and golf, not other team sports, because of the importance of the one-on-one match-up between a pitcher and a hitter in baseball.
When a player starts to have a spate of really bad or good games, fans can get involved in the psychology of "streaks" or "slumps". But Stadler says that research has shown that these supposed trends are really a matter of fans not taking in the big picture.
"It's hard for the fan to take that really long view and keep in mind the player's whole career as opposed to just the last few games' performance," he said.
Fans also tend to ignore how much baseball statistics can mask a players' actual performance. A hitter may have a sub-par batting average, though he is still hitting balls really hard—they're just hit to fielders who catch them.
In his book, Stadler mentions an interview with pitcher Greg Maddux after a streak of no-hit innings, where Maddux said he just got lucky because some guys hit balls really hard, but hit them right at a fielder.
"I think the players can kind of see that distinction in ways that, you know, because they've been around the game so much, that fans … might not be able to see that as the players are," Stadler said.
Stadler said there's a little more credence to the slump theory because a player might let his poor performance get to him and over-think his actions, so that "he's thinking about how he's swinging the bat, and that kind of self-focus really disrupts performance of something that should be a smooth and fluid skill and doesn't really need that much thought," Stadler said, sort of like if you tried to think about all the steps involved in tying your shoe.
Outside factors can also potentially affect a player's performance—the year before free agency, players often perform better, which seems to suggest that it acts as a motivation. Generally though, the extraordinary focus that players have helps them compartmentalize and keep their head in the game—even when Barry Bonds' father was dying, there was no discernible difference in his performance.
Another fan misconception is the existence of so-called clutch hitters, Stadler said. While certain hitting situations are more important in a game than others, hitters tend to try and keep them all the same in their minds, Stadler said. And when the sport of baseball is looked at as a whole, Major League Baseball is basically all one clutch-hitting situation.
"Most major league players, you know, they've risen to the top of this really steep pyramid of players, and they've kind of made the cut through high school, college, all the different levels of the minor leagues—by the time you've had such a really selective process, you've probably got almost, almost everybody there is really good at focusing under pressure," Stadler said. "So I would think that they're all pretty much clutch hitters."
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Andrea Thompson is an associate editor at Scientific American, where she covers sustainability, energy and the environment. Prior to that, she was a senior writer covering climate science at Climate Central and a reporter and editor at Live Science, where she primarily covered Earth science and the environment. She holds a graduate degree in science health and environmental reporting from New York University, as well as a bachelor of science and and masters of science in atmospheric chemistry from the Georgia Institute of Technology.